Adjuvant analgesics for neuropathic pain in palliative care
The Pain and Analgesia guidelines provide principles of diagnosing and managing neuropathic pain; see Neuropathic pain.
Neuropathic pain is common in patients with palliative care needs, particularly among those with cancer; it can be related to the cancer itself or the effects of cancer treatmentBennett, 2012Fallon, 2013Swarm, 2019. For management of painful chemotherapy-induced peripheral neuropathies, see the Pain and Analgesia guidelines.
Data to support adjuvant analgesics for neuropathic pain in palliative care are limited. The advice in this topic is extrapolated from evidence for chronic neuropathic pain in the general populationFinnerup, 2015Swarm, 2019. Although neuropathic pain usually only partially responds to opioids, opioid therapy is commonly combined with an adjuvant analgesic in patients with palliative care needs because they often experience multiple types of painFallon, 2013Swarm, 2019. For more information, see Principles of pharmacological management of pain in palliative care.
If an adjuvant analgesic is indicated for neuropathic pain, commonly used adjuvants are gabapentinoids, tricyclic antidepressants (TCAs), and serotonin and noradrenaline reuptake inhibitors (SNRIs). Choice of adjuvant depends on the general factors to guide analgesic choice listed in Factors influencing choice of analgesic in palliative care and the prescribing considerations in the Pain and Analgesia guidelines.
If a gabapentinoid is preferred for neuropathic pain in palliative care, use:
1gabapentin 100 to 300 mg orally, at night. Increase to twice daily, then 3 times daily at 3- to 7-day intervals as tolerated and according to response—see Monitoring analgesic therapy in palliative care. If needed, increase the dose at 3- to 7-day intervals up to a maximum of 3600 mg in 24 hours. For patients who are frail or older than 70 years, use the lower end of the dose range initially, titrate more slowly and do not exceed 900 mg in 24 hours1 gabapentin
OR
1pregabalin 25 to 75 mg orally, at night. Increase to twice daily after 3 to 7 days. If needed, increase the dose at 3- to 7-day intervals as tolerated and according to response, up to a maximum of 600 mg in 24 hours—see Monitoring analgesic therapy in palliative care. For patients who are frail or older than 70 years, use the lower end of the dose range initially, titrate more slowly and do not exceed 300 mg in 24 hours2. pregabalin
If a TCA is preferred for neuropathic pain in palliative care, use:
1amitriptyline 5 to 25 mg orally, at night. Increase every 3 to 7 days, as tolerated and according to response, up to 50 mg at night—see Monitoring analgesic therapy in palliative care. If no pain relief is achieved, stop treatment. If some pain relief is achieved, continue to increase the dose every 3 to 7 days, as tolerated and according to response, up to a maximum of 150 mg at night. For patients who are frail or older than 70 years, use the lower end of the dose range initially and titrate more slowly amitriptyline
OR
1nortriptyline 5 to 25 mg orally, at night. Increase every 3 to 7 days, as tolerated and according to response, up to 50 mg at night—see Monitoring analgesic therapy in palliative care. If no pain relief is achieved, stop treatment. If some pain relief is achieved, continue to increase the dose every 3 to 7 days, as tolerated and according to response, up to a maximum of 150 mg at night. For patients who are frail or older than 70 years, use the lower end of the dose range initially and titrate more slowly. nortriptyline
If an SNRI is preferred for neuropathic pain in palliative care, use:
1duloxetine 30 mg orally, in the morning. Increase every 7 days, as tolerated and according to response, up to a maximum of 120 mg in the morning—see Monitoring analgesic therapy in palliative care duloxetine
OR
1venlafaxine modified-release 37.5 to 75 mg orally, in the morning. Increase every 7 days, as tolerated and according to response, up to a maximum of 225 mg in the morning—see Monitoring analgesic therapy in palliative care. venlafaxine
Transdermal lidocaine is preferred to oral adjuvants for patients with localised neuropathic pain (eg postherpetic neuralgia, nerve entrapment)—see the Pain and Analgesia guidelines for the drug regimen.